Novel carbon nitride@polydopamine/molybdenum disulfide nanoflame retardant improves fire performance of composite coatings

An effective method to enhance the flame retardant capability of intumescent fire retardant (IFR) coatings by constructed a two-dimensional/two-dimensional (2D/2D) hybrid with good composition and microstructure. Herein, g-C3N4@PDA (CNP) was firstly obtained by loading graphite phase carbon nitride (g-C3N4) with bioinspired polydopamine (PDA). Subsequently, a novel CNP@Mo hybrids was successfully prepared by loading molybdenum disulfide onto the CNP surface via a simple one-step hydrothermal method. Then, the obtained CNP@Mo was added to the IFR coating as a synergist to improve the flame resistance. Results indicated that the addition of 2 wt% CNP@Mo to the coating effectively accelerated the formation of the char layer and reinforced its thermal insulation properties. The CNP@Mo/EP sample exhibited the lowest backside temperature (179.6 celcius), the highest expansion ratio (10.53) and the most residual char (30.7%) by fire performance test, furnace test and TGA test. The combustion performance of the IFR coatings was investigated by cone calorimeter, and the results showed that the CNP@Mo hybrids based composite coating exhibited the lowest heat release rate (HRR), total heat release rate (THR), and total smoke production value (TSP). The mechanism investigations showed that the physical barrier effect and catalytic carbonization produced by CNP@Mo hybrids during the combustion process are the main reasons for the improved flame retardancy of epoxy coatings.

Automated summary

An effective method of enhancing the flame retardant capability of intumescent fire retardant coatings was achieved by constructing a 2D/2D hybrid with molybdenum disulfide loaded onto a nitrogen-containing polydopamine material. The addition of this hybrid into the coating improved char formation and thermal insulation properties, resulting in enhanced fire performance in terms of temperature, expansion ratio, and residual char. The composite coating based on the CNP@Mo hybrids exhibited the lowest heat release rate, total heat release rate, and total smoke production value, attributing to the physical barrier effect and catalytic carbonization during combustion.